The present invention relates generally to a removable attachment for use with a rotary hand tool. More specifically, the present invention relates to a removable attachment which is adapted to be used for carving and/or planing tasks. The attachment is used in conjunction with an elongated drywall cutting bit or similar side cutting bit that is installed in the tool.
Various types of attachments are currently available for use with rotary hand tools (such as those marketed under the Dremel brand made by the S-B Power Tool Company of Chicago, Ill.) to aid the user in performing specialized tasks more accurately or more efficiently. Such attachments include various guide attachments for controlling the depth of cut and angle of penetration while performing various tasks that relate to making, maintaining and/or repairing objects or work surfaces.
Such rotary hand tools are often supplied with a flexible drive shaft that attaches to the nose portion of the hand tool itself and provides several feet of flexible extension with the bits being attached to the outer end of the extension. This enables the power unit to be suspended from a support and enables the user to control the bit rather than the power unit, which obviously is much lighter and enables more convenient usage in hard to access locations.
Manufacturers presently supply many different types of tool bits for use with such hand tools for performing tasks such as engraving, carving, polishing, cleaning, cutting, grinding, sharpening and sanding. Among the various types of cutting bits that are available are drywall cutting bits which generally have a number of flutes in the side thereof, with the end that is inserted into the collet being smooth and the cutting bit having a smooth outer end. The bits are approximately xe2x85x9 inch in diameter and may be up to 2 inches in length. The elongated drywall cutting bit as well as other side cutting bits may conveniently be used to perform carving or planing tasks with the advantage that a relatively wide swath can be made because of the length of the cutting surface of the bit. However, the control of such cutting action is in large part a function of the skill of the user in that the amount of downward force applied to the bit during operation can vary the depth of cut. The cutting action can be quite irregular due to the variation in the softness of the material that is being worked on and the dexterity of the user.
Accordingly, it is a primary object of the present invention to provide an improved carving and/or planing attachment for a rotary hand tool which enables a user to easily remove material from a work piece in a controlled incremental basis.
Another object of the present invention is to provide such an attachment which enables the user to apply varying degrees of force to the bit without gouging the work piece to any significant degree regardless of the amount of force that is applied.
Still another object of the present invention is to provide such an attachment that is simple in its design and construction, comprises a unitary piece that is easily attached and is easy to use.
Yet another object of the present invention is to provide such an attachment that is adapted to be applied to the hand tool drive unit itself, or alternatively be attached to a flexible drive shaft extension or other attachment such as a right angle attachment.
Still another object of the present invention lies in the provision for applying substantial force to the drill bit without gouging in that the attachment prevents the bit from cutting more than a known predetermined amount during any one pass across the volume of the work piece.
These and other objects of the present invention will be apparent from the following detailed description of the invention, while referring to the attached drawings in which: